I thought I should jot down a little guide to fruiting Avocados successfully in climates like mine that have low heat with cool nights where it cools down quickly in the afternoon. Specifically Southern Victoria and similar climates around the world such as Northern costal California and probably Northern areas of the South Island of New Zealand, maybe the very South of the Northern Island too (I better mention Tasmania too since it is possible to grow them there).

The major problem with growing Avocados in a place like this is not the extreme cold temps as it never drops to a level of cold that's able to damage almost any Avocado tree. With -3c being the record overnight temp. The big problem is lack of pollination due to cool overnight temps during Spring and early Summer. Luckily Avocados come in two types of flowers, the type A's the open female during the day and Type B that open female during the later afternoon and night. One you know that you need near enough to 17c worth of temp to pollinate an Avocado flower you don't have to be a rocket surgeon to realise that Type B avocados are only very rarely going to pollinate. You can still get away with it inside a city like Melbourne where the overnight temps are much higher than the surrounding area (might work deep inside San Francisco too) but outside of these heat island type climates Type B's are only majorly useful as male pollinators.

The next thing is the race of Avocado, Guatemalan types tend to grow stronger than the others during cool temps and they also flower later both of which are traits we are looking for, these all give us massive heavy fruit set during cool temps which is the goal . So what do we need? well simply any Type A Guatemalan tree such as Hass, Lamb Hass or Reed or several other similar varieties.

Hass is good to pick from (swap this around if you are in the Northern Hemisphere) April-May till late September with possibly a few hanging on into October. Lamb Hass is a month or two later and Reed also later than Hass. Reed (and I assume Lamb Hass since I don't have one) also flower later than Hass. For a type A pollinator you can choose either Bacon, Fuerte or Ettinger. Bacon tends to crop the most of these three but the quality of fruit is better on Fuerte and Ettinger. I've had crops of near enough to 100 fruit on Bacon and almost that on Fuerte (really hit and miss though), This year is the first year I've got a decent set of fruit on an Ettinger tree, it's only going to be 20 or so fruit but that's better than the usual zero. All this is nothing compared to Hass which crops 100+ every year even on the off years and looks to be in the 200-300 range this year, I can certainly see that with some more size 500+ fruit on a Hass tree is well within reach. Ettinger is the latest to flower so is the best pollinator match but it also sets the least fruit.... so this is a decision you have to make. These Type B's all ripen in Late Spring and Early Summer (Late November-Early January) and have a fairly short season. But between the two types you _almost_ get Avocados all year apart from a bit of a rest during stone fruit and apple season which I think is a great thing

There are Avocado and White Sapotes both growing well in Tasmania, the temps in Hobart are not much cooler than where I live, I think overall it's warmer than the Southern NZ, South NZ is a really cold and far South place. There's a large White Sapote tree in the Hobart gardens that's on TV almost every week on the gardening show they do from there. The Ocean surrounding me is just as cold and comes straight up from the Southern ocean anyway so I may as well be in Tasmania, it's only the days where the wind comes down from the North that make the averages and extremes warmer, then again that extreme hot wind from the desert is plenty capable of crossing the sea to Tasmania and hitting them with 40c+ days also.

Jason, I like your comments here! I'm curious about how you space your avos. What kind of A/B ratio do you use, and how far apart? I've heard of ultra-high density planting people who say the foliage should be touching, but there are lots of very high producing avo orchards in NZ that have only Hass and no type B at all.

Do you find Ettinger better than other B types for pollination?

Have you watched closely the flowering times to try to match them, or do the flowering times vary according to climate?

Ben, I have about 4.5 meters between the trees when they are planted beside each other but most of them are not next to another Avocado. If they were all round shaped trees like Hass that would have had them all touching by now. But I mostly planted different trees beside each other so the roots wouldn't be competing at the same level in the soil.

I don't think you NEED a pollinator for Hass but I'm sure it's better with one, everything I've read about it says they increase production with one. I use the seeds for rootstocks when I'm growing more trees too and I'd rather have a cross pollinated rootstock than a self pollinated one and it should make the fruit larger also .

The Isrealies prefer Ettinger to pollinate Hass because it flowers at the same time for them + the bees like it the most and they could have used any variety they wanted, that's how come I got a Ettinger in the first place. Apparently Bacon pollinates Hass well also but it doesn't flower late so I'm not so keen on it.

Ettinger does flower at the same time exactly as Hass for me too, almost everything else is earlier than Hass so during the last half of the flowering of Hass when most of the fruit set happens the only type B that's still flowering is Ettinger anyway. My best Hass tree is planted with one Ettinger tree about 15 meters away in one direction and another about 10 meters away in another direction and the fruit set is huge, really just as much as the tree can carry.

If I was going to have a commercial Avocado orchard in a climate like this (you really could make a profit from it) I'd plant Hass and Reed with a sprinkling of Ettinger trees through the orchard for pollination only, if you happened to get fruit from the Ettingers that would be a bonus. That would only give you a Autumn/Winter/Spring crop if you only counted Hass and Reed but you can't be playing with Avocados all the time . Check this out

This is a great info. I guess we can say any late blooming type B should work as a pollinator for late blooming type A such as Hass to increase production? Of course such information is hard to find, I don't know of any other besides Ettinger that you mentioned.

Anthony, I'm sure any late flowering type B Guatemalan would be a good match but for whatever reason there doesn't seem to been any/many of those selected. At least there's none that I know of and are on possible to get hold of

SJVcharlie wrote:We grow Hass commercially in the San Joaquin Valley of California. We consider Bacon and Fuerte the best for cross pollination.

Have you tried Ettinger? Ettinger seems to have a 3-day male stage and a later flowering date than Bacon or Fuerte in NZ, so better for marginal pollination seasons. I'm intending to try Ettinger, haven't got any yet.